Furan 3-acetyl-2,4-dimethyl

Benzo[6]furan, 2-acetyl-4,7-dimethyl-3-isopropyl-UV, 4, 589 (73A3O1069)... 

H-Benzo[a]carbazole, 4,4a,5,l 1,1 la,l Ib-hexahydro-synthesis, 4, 283 Benzo[b]carbazole, N-acetyl-photochemical rearrangements, 4, 204 Benzo[/]chroman-4-one, 9-hydroxy-2,2-dimethyl-synthesis, 3, 851 Benzochromanones synthesis, 3, 850, 851, 855 Benzochromones synthesis, 3, 821 Benzocinnoline-N-imide ring expansion, 7, 255 Benzocinnolines synthesis, 2, 69, 75 UV, 2, 127 Benzocoumarins synthesis, 3, 810 Benzo[15]crown-5 potassium complex crystal stmcture, 7, 735 sodium complex crystal stmcture, 7, 735 Benzo[ 18]cr own-6 membrane transport and, 7, 756 Benzo[b]cyclohepta[d]furans synthesis, 4, 106 Benzocycloheptathi azoles synthesis, 5, 120... 

Benzo[b]furan, 2,3-dihydro-2-phenyl-synthesis, 4, 697 Benzo[b]furan, 2,3-dihydroxy-tautomerism, 4, 37 Benzo[6]furan, 4,6-dimethoxy-acylation, 4, 606 Benzo[6]furan, 2,3-dimethyl-acetylation, 4, 606 bromination, 4, 605 photooxygenation, 4, 642 Benzo[b]furan, 5,6-dimethyl-2,3-diphenyl-applications, 4, 709 Benzo[b]furan, 1,3-diphenyl-vertical ionization potential, 4, 587 Benzo[b]furan, 2-ethoxy-5-hydroxy-synthesis, 4, 127... 

Furan, 3-acetoxy-2,4,5-triphenyl-synthesis, 4, 659 Furan, 2-acetyl-isopropylation, 4, 607 rotamers, 4, 544 synthesis, 4, 665 toxicity, 1, 136 Furan, 3-acetyl-bromination, 4, 604 Furan, 3-acetyI-2-amino-reactions, 4, 74 Furan, 2-acetyl-3,5-dimethyl-synthesis, 4, 691 Furan, 2-acetyl-5-ethyl-synthesis, 4, 691 Furan, 2-acetyl-3-hydroxy-synthesis, 4, 649... 

Acetylenedicarboxylic acid, dimethyl ester, 50, 25, 36 Acetylenes, reaction with tri-methylsilyl azide, 50, 109 Acetylenic sulfonium salts, furans from, 53, 3 2-Acetylindane-l,3-dione, 52, 4 2-ACETYL-6-METHOXYNAPHTHALENE, 53, 5... 

Another method of functionalizing 72 was initiated by catalytically hydrogenating 78 to 79. Thermolysis of 79 at 220 °C under vacuum resulted in an ethylene extrusion to generate furan 80. Diels-Alder reaction of 80 with dimethyl acetyle-nedicarboxylate (DMAD) provided endoxide 81, which on subsequent deoxygenation with low-valent titanium gave ester 82 (Scheme 17). ... 

Methoxy-6-propyl-l,4-benzoquinone (170, Scheme 43) with hydrogen chloride undergoes dimerization and yields the biquinone 171 and the di-benzofuran 172. 2-Hydroxy-3,6-dimethyl-1,4-benzoquinone (173, Scheme 44), however, on treatment with boron trifluoride etherate in ether, or with concentrated sulfuric acid in acetic acid at room temperature, yields the extended quinone 174, which on reductive acetylation affords the dibenzo-furan 175. 

The reaction of a-bromoacetals with trimethylsilylenolates catalyzed by titanium tetrachloride provides /3-alkoxy-y-bromoketones, which are useful furan precursors (Scheme 33) (75CL527). A new synthesis of acylfurans is exemplified by the formation of the 3-acetyl derivative (146) by heating the brdmoalkene (145) (78JOC4596). 2,2-Dimethyl-3(2//)-furanone (148) has been synthesized from 3-hydroxy-3-methylbutan-2-one treatment with sodium hydride and ethyl formate gave the hydroxymethylene derivative (147), which was cyclized and dehydrated to the furanone (148) with hydrochloric acid (Scheme 34) (71TL4891). O... 

Phenyl-A2-oxazolin-4-one forms the furan (282) on treatment with dimethyl acetyl-enedicarboxylate. The reaction may be interpreted as proceeding through a Diels-Alder addition to the tautomeric oxazole (281) (Scheme 74) (72CC1000). 

C) Preparation of 2-Acetyl-3-Methyl-5-(2-Oxo-2,5-Dihydro-4-Furyl)Benro[b]Furan (3556 CB) (1) A suspension of 2 grams of the compound prepared according to (B) in 20 ml of concentrated hydrochloric acid, is heated to about 50°C, just until it dissolves. There after it is heated for 2 minutes to 70°C, just until precipitation commences. The mixture is allowed to cool, diluted with water, filtered, the residue washed, dried, and sublimed at 200°C and 0.1 mm pressure. 1.4 grams of product (Yield 70%) is obtained. MPc=218°-221°C. A second sublimation produces a chemically pure product. MPC= 221°-222°C. (2) Compound 1567 CB and chloracetone are caused to react as in (B), the mineral salts subsequently filtered, 12 ml of concentrated hydrochloric acid are added to the solution in dimethyl formamide without dilution with water, and the mixture heated for 40 minutes on a water bath. The product crystallizes in the warm mixture, the mixture is cooled to room temperature, filtered, the residue washed with water and crystallized from acetic acid. MPC= 222°C. Yield 60% based on compound 1567 CB. 

Other furans included methyl- 2-furfural [4], 2-acetylfuran [5], 2-propionylfuran [6], l-(2-furanyl)-2-propanone [7] and l-(-2-furanyl)-3-butanone [8]. Several alkylpyrazines were also found, with the 2,5-dimethyl [9] and 2-methy 1-5-ethyl [10] the most abundant derivatives, and some 2-acyl-l-methylpyrroles of which only the formyl [11] and acetyl [12] derivatives were conclusively identified. 

Pyrroles and furans also undergo the Gattermann aldehyde synthesis with HC1 and HGN, furan gives furfuralde-hyde. The HoubenHoesch ketone synthesis is also applicable to the preparation of acyl derivatives of furans and pyrroles, e.g., ethyl 2,4-dimethylpyrrole-3-carboxylate with MeCN and HC1 yields ethyl 5-acetyl-2,4-dimethyl-3-carboxylate. 

Acetyl-2,5-dimethyl Furan 643 Benzyl Propionate 661 Type... 

Acetyl-2,5-dimethyl Furan View F avor Chemjca ... 

Cyclopropanation products were not isolated from furan and the following diazocarbonyl compounds diethyl 2-diazopent-3-enedioate, ° dimethyl diazomalonate (see also Table 13, entry 9), 6-diazopenicillinates (though not with benzofuran). The carbenoid reaction [copper(II) sulfate, 80 °C] of l-diazopropan-2-one with benzofuran yields 1-acetyl-1 a,6b-dihydro-l//-cyclopropa[ )]benzofuran. ° However, when furan is cyclopropanated with a-di-azo ketones, 6-(l-oxoalkyl)-2-oxabicyclo[3.1.0]hex-3-enes are either not obtained or rearrange slowly even at 20°C to the isomeric 1,4-diacylbuta-l,3-dienes. 

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